summaryrefslogtreecommitdiffstats
path: root/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
blob: fcaa351bf2d31cf08521315848ffc0a364432e73 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
/** @file
*
*  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
*
*  This program and the accompanying materials
*  are licensed and made available under the terms and conditions of the BSD License
*  which accompanies this distribution.  The full text of the license may be found at
*  http://opensource.org/licenses/bsd-license.php
*
*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
*
**/

#include "Lan9118Dxe.h"


typedef struct {
  MAC_ADDR_DEVICE_PATH      Lan9118;
  EFI_DEVICE_PATH_PROTOCOL  End;
} LAN9118_DEVICE_PATH;

LAN9118_DEVICE_PATH Lan9118PathTemplate =  {
  {
    {
      MESSAGING_DEVICE_PATH, MSG_MAC_ADDR_DP,
      { (UINT8) (sizeof(MAC_ADDR_DEVICE_PATH)), (UINT8) ((sizeof(MAC_ADDR_DEVICE_PATH)) >> 8) }
    },
    { 0 },
    0
  },
  {
    END_DEVICE_PATH_TYPE,
    END_ENTIRE_DEVICE_PATH_SUBTYPE,
    sizeof(EFI_DEVICE_PATH_PROTOCOL),
    0
  }
};

/*
**  Entry point for the LAN9118 driver
**
*/
EFI_STATUS
Lan9118DxeEntry (
  IN EFI_HANDLE Handle,
  IN EFI_SYSTEM_TABLE *SystemTable
  )
{
  EFI_STATUS                   Status;
  LAN9118_DRIVER              *LanDriver;
  EFI_SIMPLE_NETWORK_PROTOCOL *Snp;
  EFI_SIMPLE_NETWORK_MODE     *SnpMode;
  LAN9118_DEVICE_PATH         *Lan9118Path;
  EFI_HANDLE                   ControllerHandle;

  // The PcdLan9118DxeBaseAddress PCD must be defined
  ASSERT (PcdGet32 (PcdLan9118DxeBaseAddress) != 0);

  // Allocate Resources
  LanDriver = AllocateZeroPool (sizeof (LAN9118_DRIVER));
  if (LanDriver == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
  Lan9118Path = (LAN9118_DEVICE_PATH*)AllocateCopyPool (sizeof (LAN9118_DEVICE_PATH), &Lan9118PathTemplate);
  if (Lan9118Path == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  // Initialize pointers
  Snp = &(LanDriver->Snp);
  SnpMode = &(LanDriver->SnpMode);
  Snp->Mode = SnpMode;

  // Set the signature of the LAN Driver structure
  LanDriver->Signature = LAN9118_SIGNATURE;

  // Assign fields and func pointers
  Snp->Revision = EFI_SIMPLE_NETWORK_PROTOCOL_REVISION;
  Snp->WaitForPacket = NULL;
  Snp->Initialize = SnpInitialize;
  Snp->Start = SnpStart;
  Snp->Stop = SnpStop;
  Snp->Reset = SnpReset;
  Snp->Shutdown = SnpShutdown;
  Snp->ReceiveFilters = SnpReceiveFilters;
  Snp->StationAddress = SnpStationAddress;
  Snp->Statistics = SnpStatistics;
  Snp->MCastIpToMac = SnpMcastIptoMac;
  Snp->NvData = SnpNvData;
  Snp->GetStatus = SnpGetStatus;
  Snp->Transmit = SnpTransmit;
  Snp->Receive = SnpReceive;

  // Start completing simple network mode structure
  SnpMode->State = EfiSimpleNetworkStopped;
  SnpMode->HwAddressSize = NET_ETHER_ADDR_LEN; // HW address is 6 bytes
  SnpMode->MediaHeaderSize = sizeof(ETHER_HEAD); // Not sure of this
  SnpMode->MaxPacketSize = EFI_PAGE_SIZE; // Preamble + SOF + Ether Frame (with VLAN tag +4bytes)
  SnpMode->NvRamSize = 0;           // No NVRAM with this device
  SnpMode->NvRamAccessSize = 0; // No NVRAM with this device

  // Update network mode information
  SnpMode->ReceiveFilterMask = EFI_SIMPLE_NETWORK_RECEIVE_MULTICAST |
                                 EFI_SIMPLE_NETWORK_RECEIVE_UNICAST |
                                 EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST |
                                 EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS;/* |
                                 EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST;*/
  // Current allowed settings
  SnpMode->ReceiveFilterSetting = EFI_SIMPLE_NETWORK_RECEIVE_MULTICAST |
                                    EFI_SIMPLE_NETWORK_RECEIVE_UNICAST |
                                    EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST;

  // LAN9118 has 64bit hash table, can filter 64 MCast MAC Addresses
  SnpMode->MaxMCastFilterCount = MAX_MCAST_FILTER_CNT;
  SnpMode->MCastFilterCount = 0;
  ZeroMem (&SnpMode->MCastFilter, MAX_MCAST_FILTER_CNT * sizeof(EFI_MAC_ADDRESS));

  // Set the interface type (1: Ethernet or 6: IEEE 802 Networks)
  SnpMode->IfType = NET_IFTYPE_ETHERNET;

  // Mac address is changeable as it is loaded from erasable memory
  SnpMode->MacAddressChangeable = TRUE;

  // Can only transmit one packet at a time
  SnpMode->MultipleTxSupported = FALSE;

  // MediaPresent checks for cable connection and partner link
  SnpMode->MediaPresentSupported = TRUE;
  SnpMode->MediaPresent = FALSE;

  // Set broadcast address
  SetMem (&SnpMode->BroadcastAddress, sizeof (EFI_MAC_ADDRESS), 0xFF);

  // Power up the device so we can find the MAC address
  Status = Lan9118Initialize (Snp);
  if (EFI_ERROR (Status)) {
    DEBUG ((EFI_D_ERROR, "Lan9118: Error initialising hardware\n"));
    return EFI_DEVICE_ERROR;
  }

  // Assign fields for device path
  CopyMem (&Lan9118Path->Lan9118.MacAddress, &Snp->Mode->CurrentAddress, NET_ETHER_ADDR_LEN);
  Lan9118Path->Lan9118.IfType = Snp->Mode->IfType;

  // Initialise the protocol
  ControllerHandle = NULL;
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &ControllerHandle,
                  &gEfiSimpleNetworkProtocolGuid, Snp,
                  &gEfiDevicePathProtocolGuid, Lan9118Path,
                  NULL
                  );
  // Say what the status of loading the protocol structure is
  if (EFI_ERROR(Status)) {
    FreePool (LanDriver);
  } else {
    LanDriver->ControllerHandle = ControllerHandle;
  }

  return Status;
}

/*
 *  UEFI Start() function
 *
 *  Parameters:
 *
 *  @param Snp:  A pointer to the EFI_SIMPLE_NETWORK_PROTOCOL instance.
 *
 *  Description:
 *
 *    This function starts a network interface. If the network interface successfully starts, then
 *    EFI_SUCCESS will be returned.
 */
EFI_STATUS
EFIAPI
SnpStart (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp
 )
{
  // Check Snp instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // Check state
  if ((Snp->Mode->State == EfiSimpleNetworkStarted) || (Snp->Mode->State == EfiSimpleNetworkInitialized)) {
    return EFI_ALREADY_STARTED;
  } else if (Snp->Mode->State == EfiSimpleNetworkMaxState) {
    return EFI_DEVICE_ERROR;
  }

  // Change state
  Snp->Mode->State = EfiSimpleNetworkStarted;
  return EFI_SUCCESS;
}

/*
 *  UEFI Stop() function
 *
 */
EFI_STATUS
EFIAPI
SnpStop (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp
  )
{
  // Check Snp Instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // Check state of the driver
  if ((Snp->Mode->State == EfiSimpleNetworkStopped) || (Snp->Mode->State == EfiSimpleNetworkMaxState)) {
    return EFI_NOT_STARTED;
  }

  // Stop the Tx and Rx
  StopTx (STOP_TX_CFG | STOP_TX_MAC, Snp);
  StopRx (0, Snp);

  // Change the state
  switch (Snp->Mode->State) {
    case EfiSimpleNetworkStarted:
    case EfiSimpleNetworkInitialized:
      Snp->Mode->State = EfiSimpleNetworkStopped;
      break;
    default:
      return EFI_DEVICE_ERROR;
  }

  // Put the device into a power saving mode ?
  return EFI_SUCCESS;
}


// Allocated receive and transmit buffers
STATIC UINT32 gTxBuffer = 0;

/*
 *  UEFI Initialize() function
 *
 */
EFI_STATUS
EFIAPI
SnpInitialize (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
  IN        UINTN                        RxBufferSize    OPTIONAL,
  IN        UINTN                        TxBufferSize    OPTIONAL
  )
{
  EFI_STATUS Status;
  UINT32     PmConf;
  INT32      AllocResult;
  UINT32     RxStatusSize;
  UINT32     TxStatusSize;

  // Initialize variables
  // Global variables to hold tx and rx FIFO allocation
  gTxBuffer = 0;

  // Check Snp Instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // First check that driver has not already been initialized
  if (Snp->Mode->State == EfiSimpleNetworkInitialized) {
    DEBUG ((EFI_D_WARN, "LAN9118 Driver already initialized\n"));
    return EFI_SUCCESS;
  } else
  if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "LAN9118 Driver not started\n"));
    return EFI_NOT_STARTED;
  }

  // Initiate a PHY reset
  if (PhySoftReset (PHY_RESET_PMT | PHY_RESET_CHECK_LINK, Snp) < 0) {
    Snp->Mode->State = EfiSimpleNetworkStopped;
    DEBUG ((EFI_D_WARN, "Warning: Link not ready after TimeOut. Check ethernet cable\n"));
    return EFI_NOT_STARTED;
  }

  // Initiate a software reset
  Status = SoftReset (0, Snp);
  if (EFI_ERROR(Status)) {
    DEBUG ((EFI_D_WARN, "Soft Reset Failed: Hardware Error\n"));
    return EFI_DEVICE_ERROR;
  }

  // Read the PM register
  PmConf = MmioRead32 (LAN9118_PMT_CTRL);

  // MPTCTRL_WOL_EN: Allow Wake-On-Lan to detect wake up frames or magic packets
  // MPTCTRL_ED_EN:  Allow energy detection to allow lowest power consumption mode
  // MPTCTRL_PME_EN: Allow Power Management Events
  PmConf = 0;
  PmConf |= (MPTCTRL_WOL_EN | MPTCTRL_ED_EN | MPTCTRL_PME_EN);

  // Write the current configuration to the register
  MmioWrite32 (LAN9118_PMT_CTRL, PmConf);
  gBS->Stall (LAN9118_STALL);
  gBS->Stall (LAN9118_STALL);

  // Configure GPIO and HW
  Status = ConfigureHardware (HW_CONF_USE_LEDS, Snp);
  if (EFI_ERROR(Status)) {
    return Status;
  }

  // Assign the transmitter buffer size (default values)
  TxStatusSize = LAN9118_TX_STATUS_SIZE;
  RxStatusSize = LAN9118_RX_STATUS_SIZE;

  // Check that a buff size was specified
  if (TxBufferSize > 0) {
    if (RxBufferSize == 0) {
      RxBufferSize = LAN9118_RX_DATA_SIZE;
    }

    AllocResult = ChangeFifoAllocation (
                          ALLOC_USE_FIFOS,
                          &TxBufferSize,
                          &RxBufferSize,
                          &TxStatusSize,
                          &RxStatusSize,
                          Snp
                          );

    if (AllocResult < 0) {
      return EFI_OUT_OF_RESOURCES;
    }
  }

  // Do auto-negotiation if supported
  Status = AutoNegotiate (AUTO_NEGOTIATE_ADVERTISE_ALL, Snp);
  if (EFI_ERROR(Status)) {
    DEBUG ((EFI_D_WARN, "Lan9118: Auto Negociation not supported.\n"));
  }

  // Configure flow control depending on speed capabilities
  Status = ConfigureFlow (0, 0, 0, 0, Snp);
  if (EFI_ERROR(Status)) {
    return Status;
  }

  // Enable the receiver and transmitter
  Status = StartRx (0, Snp);
  if (EFI_ERROR(Status)) {
    return Status;
  }

  Status = StartTx (START_TX_MAC | START_TX_CFG, Snp);
  if (EFI_ERROR(Status)) {
    return Status;
  }

  // Now acknowledge all interrupts
  MmioWrite32 (LAN9118_INT_STS, ~0);

  // Declare the driver as initialized
  Snp->Mode->State = EfiSimpleNetworkInitialized;

  return Status;
}

/*
 *  UEFI Reset () function
 *
 */
EFI_STATUS
EFIAPI
SnpReset (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
  IN        BOOLEAN Verification
  )
{
  UINT32 PmConf;
  UINT32 HwConf;
  UINT32 ResetFlags;

  PmConf = 0;
  HwConf = 0;
  ResetFlags = 0;

  // Check Snp Instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // First check that driver has not already been initialized
  if (Snp->Mode->State == EfiSimpleNetworkStarted) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not yet initialized\n"));
    return EFI_DEVICE_ERROR;
  } else if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not started\n"));
    return EFI_NOT_STARTED;
  }

  // Initiate a PHY reset
  if (PhySoftReset (PHY_RESET_PMT | PHY_RESET_CHECK_LINK, Snp) < 0) {
    Snp->Mode->State = EfiSimpleNetworkStopped;
    return EFI_NOT_STARTED;
  }

  // Initiate a software reset
  ResetFlags |= SOFT_RESET_CHECK_MAC_ADDR_LOAD | SOFT_RESET_CLEAR_INT;

  if (Verification) {
    ResetFlags |= SOFT_RESET_SELF_TEST;
  }

  if (SoftReset (ResetFlags, Snp) < 0) {
    DEBUG ((EFI_D_WARN, "Warning: Soft Reset Failed: Hardware Error\n"));
    return EFI_DEVICE_ERROR;
  }

  // Read the PM register
  PmConf = MmioRead32 (LAN9118_PMT_CTRL);

  // MPTCTRL_WOL_EN: Allow Wake-On-Lan to detect wake up frames or magic packets
  // MPTCTRL_ED_EN:  Allow energy detection to allow lowest power consumption mode
  // MPTCTRL_PME_EN: Allow Power Management Events
  PmConf |= (MPTCTRL_WOL_EN | MPTCTRL_ED_EN | MPTCTRL_PME_EN);

  // Write the current configuration to the register
  MmioWrite32 (LAN9118_PMT_CTRL, PmConf);
  gBS->Stall (LAN9118_STALL);

  // Check that a buffer size was specified in SnpInitialize
  if (gTxBuffer != 0) {
    HwConf = MmioRead32 (LAN9118_HW_CFG);        // Read the HW register
    HwConf &= ~HW_CFG_TX_FIFO_SIZE_MASK;         // Clear buffer bits first
    HwConf |= HW_CFG_TX_FIFO_SIZE(gTxBuffer);    // assign size chosen in SnpInitialize

    MmioWrite32 (LAN9118_HW_CFG, HwConf);        // Write the conf
    gBS->Stall (LAN9118_STALL);
  }

  // Enable the receiver and transmitter and clear their contents
  StartRx (START_RX_CLEAR, Snp);
  StartTx (START_TX_MAC | START_TX_CFG | START_TX_CLEAR, Snp);

  // Now acknowledge all interrupts
  MmioWrite32 (LAN9118_INT_STS, ~0);

  return EFI_SUCCESS;
}

/*
 *  UEFI Shutdown () function
 *
 */
EFI_STATUS
EFIAPI
SnpShutdown (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp
  )
{
  // Check Snp Instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // First check that driver has not already been initialized
  if (Snp->Mode->State == EfiSimpleNetworkStarted) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not yet initialized\n"));
    return EFI_DEVICE_ERROR;
  } else if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver in stopped state\n"));
    return EFI_NOT_STARTED;
  }

  // Initiate a PHY reset
  PhySoftReset (PHY_RESET_PMT, Snp);

  // Initiate a software reset
  if (SoftReset (0, Snp) < 0) {
    DEBUG ((EFI_D_WARN, "Warning: Soft Reset Failed: Hardware Error\n"));
    return EFI_DEVICE_ERROR;
  }

  return EFI_SUCCESS;
}


/*
 *  UEFI ReceiveFilters() function
 *
 */
EFI_STATUS
EFIAPI
SnpReceiveFilters (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
  IN        UINT32 Enable,
  IN        UINT32 Disable,
  IN        BOOLEAN Reset,
  IN        UINTN NumMfilter          OPTIONAL,
  IN        EFI_MAC_ADDRESS *Mfilter  OPTIONAL
  )
{
  UINT32 MacCSRValue;
  UINT32 MultHashTableHigh;
  UINT32 MultHashTableLow;
  UINT32 Crc;
  UINT8 BitToSelect;
  UINT32 Count;

  MacCSRValue = 0;
  MultHashTableHigh = 0;
  MultHashTableLow = 0;
  Crc = 0xFFFFFFFF;
  BitToSelect = 0;
  Count = 0;

  // Check that driver was started and initialised
  if (Snp->Mode->State == EfiSimpleNetworkStarted) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not initialized\n"));
    return EFI_DEVICE_ERROR;
  } else if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver in stopped state\n"));
    return EFI_NOT_STARTED;
  }

  // If reset then clear the filter registers
  if (Reset) {
    Enable |= EFI_SIMPLE_NETWORK_RECEIVE_MULTICAST;
    IndirectMACWrite32 (INDIRECT_MAC_INDEX_HASHL, 0x00000000);
    IndirectMACWrite32 (INDIRECT_MAC_INDEX_HASHH, 0x00000000);
  }

  // Set the hash tables
  if ((NumMfilter > 0) && (!Reset)) {

    // Read the Multicast High Hash Table
    MultHashTableHigh = IndirectMACRead32 (INDIRECT_MAC_INDEX_HASHH);

    // Read the Multicast Low Hash Table
    MultHashTableLow = IndirectMACRead32 (INDIRECT_MAC_INDEX_HASHL);

    // Go through each filter address and set appropriate bits on hash table
    for (Count = 0; Count < NumMfilter; Count++) {

      // Generate a 32-bit CRC for Ethernet
      Crc = GenEtherCrc32 (&Mfilter[Count],6);
      //gBS->CalculateCrc32 ((VOID*)&Mfilter[Count],6,&Crc); <-- doesn't work as desired

      // Get the most significant 6 bits to index hash registers
      BitToSelect = (Crc >> 26) & 0x3F;

      // Select hashlow register if MSB is not set
      if ((BitToSelect & 0x20) == 0) {
        MultHashTableLow |= (1 << BitToSelect);
      } else {
        MultHashTableHigh |= (1 << (BitToSelect & 0x1F));
      }
    }

    // Write the desired hash
    IndirectMACWrite32 (INDIRECT_MAC_INDEX_HASHL, MultHashTableLow);
    IndirectMACWrite32 (INDIRECT_MAC_INDEX_HASHH, MultHashTableHigh);
  }

  // Read MAC controller
  MacCSRValue = IndirectMACRead32 (INDIRECT_MAC_INDEX_CR);

  // Set the options for the MAC_CSR
  if (Enable & EFI_SIMPLE_NETWORK_RECEIVE_UNICAST) {
    StartRx (0, Snp);
    DEBUG ((DEBUG_NET, "Allowing Unicast Frame Reception\n"));
  }

  if (Disable & EFI_SIMPLE_NETWORK_RECEIVE_UNICAST) {
    StopRx (0, Snp);
    DEBUG ((DEBUG_NET, "Disabling Unicast Frame Reception\n"));
  }

  if (Enable & EFI_SIMPLE_NETWORK_RECEIVE_MULTICAST) {
    MacCSRValue |= MACCR_HPFILT;
    DEBUG ((DEBUG_NET, "Allowing Multicast Frame Reception\n"));
  }

  if (Disable & EFI_SIMPLE_NETWORK_RECEIVE_MULTICAST) {
    MacCSRValue &= ~MACCR_HPFILT;
    DEBUG ((DEBUG_NET, "Disabling Multicast Frame Reception\n"));
  }

  if (Enable & EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST) {
    MacCSRValue &= ~(MACCR_BCAST);
    DEBUG ((DEBUG_NET, "Allowing Broadcast Frame Reception\n"));
  }

  if (Disable & EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST) {
    MacCSRValue |= MACCR_BCAST;
    DEBUG ((DEBUG_NET, "Disabling Broadcast Frame Reception\n"));
  }

  if (Enable & EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS) {
    MacCSRValue |= MACCR_PRMS;
    DEBUG ((DEBUG_NET, "Enabling Promiscuous Mode\n"));
  }

  if (Disable & EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS) {
    MacCSRValue &= ~MACCR_PRMS;
    DEBUG ((DEBUG_NET, "Disabling Promiscuous Mode\n"));
  }

  if (Enable & EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST) {
    MacCSRValue |= (MACCR_HPFILT | MACCR_PRMS);
    DEBUG ((DEBUG_NET, "Enabling Promiscuous Multicast Mode\n"));
  }

  if (Disable & EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST) {
    MacCSRValue &= ~(MACCR_HPFILT | MACCR_PRMS);
    DEBUG ((DEBUG_NET, "Disabling Promiscuous Multicast Mode\n"));
  }

  // Write the options to the MAC_CSR
  IndirectMACWrite32 (INDIRECT_MAC_INDEX_CR, MacCSRValue);
  gBS->Stall (LAN9118_STALL);

  return EFI_SUCCESS;
}

/*
 *  UEFI StationAddress() function
 *
 */
EFI_STATUS
EFIAPI
SnpStationAddress (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL *Snp,
  IN        BOOLEAN Reset,
  IN        EFI_MAC_ADDRESS *NewMac
)
{
  DEBUG ((DEBUG_NET, "SnpStationAddress()\n"));

  UINT32 Count;
  UINT8  PermAddr[6];
  UINT64 DefaultMacAddress;

  Count = 0;

  // Check Snp instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // Check that driver was started and initialised
  if (Snp->Mode->State == EfiSimpleNetworkStarted) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not initialized\n"));
    return EFI_DEVICE_ERROR;
  } else if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver in stopped state\n"));
    return EFI_NOT_STARTED;
  }

  // Get the Permanent MAC address if need reset
  if (Reset) {
    // Try using EEPROM first. Read the first byte of data from EEPROM at the address 0x0
    if ((IndirectEEPROMRead32 (0) & 0xFF) == EEPROM_EXTERNAL_SERIAL_EEPROM) {
      for (Count = 1; Count < 7; Count++) {
        PermAddr[Count - 1] = IndirectEEPROMRead32 (Count);
      }

      // Write address
      Lan9118SetMacAddress ((EFI_MAC_ADDRESS *) PermAddr, Snp);
    } else {
      DEBUG ((EFI_D_ERROR, "Lan9118: Warning: No valid MAC address in EEPROM, using fallback\n"));
      DefaultMacAddress = FixedPcdGet64 (PcdLan9118DefaultMacAddress);
      Lan9118SetMacAddress ((EFI_MAC_ADDRESS *) &DefaultMacAddress, Snp);
    }
  } else {
    // Otherwise use the specified new MAC address
    if (NewMac == NULL) {
      return EFI_INVALID_PARAMETER;
    }

    // Write address
    Lan9118SetMacAddress (NewMac, Snp);
  }

  return EFI_SUCCESS;
}

/*
 *  UEFI Statistics() function
 *
 */
EFI_STATUS
EFIAPI
SnpStatistics (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
  IN        BOOLEAN Reset,
  IN  OUT   UINTN *StatSize,
      OUT   EFI_NETWORK_STATISTICS *Statistics
  )
{
  LAN9118_DRIVER *LanDriver;

  LanDriver = INSTANCE_FROM_SNP_THIS (Snp);

  DEBUG ((DEBUG_NET, "SnpStatistics()\n"));

  // Check Snp instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // Check that driver was started and initialised
  if (Snp->Mode->State == EfiSimpleNetworkStarted) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not initialized\n"));
    return EFI_DEVICE_ERROR;
  } else if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver in stopped state\n"));
    return EFI_NOT_STARTED;
  }

  // Check pointless condition
  if ((!Reset) && (StatSize == NULL) && (Statistics == NULL)) {
    return EFI_SUCCESS;
  }

  // Check the parameters
  if ((StatSize == NULL) && (Statistics != NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  // Do a reset if required
  if (Reset) {
    ZeroMem (&LanDriver->Stats, sizeof(EFI_NETWORK_STATISTICS));
  }

  // Check buffer size
  if (*StatSize < sizeof(EFI_NETWORK_STATISTICS)) {
    *StatSize = sizeof(EFI_NETWORK_STATISTICS);
    return EFI_BUFFER_TOO_SMALL;
  }

  // Fill in the statistics
  CopyMem(&Statistics, &LanDriver->Stats, sizeof(EFI_NETWORK_STATISTICS));

  return EFI_SUCCESS;
}

/*
 *  UEFI MCastIPtoMAC() function
 *
 */
EFI_STATUS
EFIAPI
SnpMcastIptoMac (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
  IN        BOOLEAN IsIpv6,
  IN        EFI_IP_ADDRESS *Ip,
      OUT   EFI_MAC_ADDRESS *McastMac
  )
{
  DEBUG ((DEBUG_NET, "SnpMcastIptoMac()\n"));

  // Check Snp instance
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  // Check that driver was started and initialised
  if (Snp->Mode->State == EfiSimpleNetworkStarted) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver not initialized\n"));
    return EFI_DEVICE_ERROR;
  } else if (Snp->Mode->State == EfiSimpleNetworkStopped) {
    DEBUG ((EFI_D_WARN, "Warning: LAN9118 Driver in stopped state\n"));
    return EFI_NOT_STARTED;
  }

  // Check parameters
  if ((McastMac == NULL) || (Ip == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  // Make sure MAC address is empty
  ZeroMem (McastMac, sizeof(EFI_MAC_ADDRESS));

  // If we need ipv4 address
  if (!IsIpv6) {
    // Most significant 25 bits of a multicast HW address are set.
    // 01-00-5E is the IPv4 Ethernet Multicast Address (see RFC 1112)
    McastMac->Addr[0] = 0x01;
    McastMac->Addr[1] = 0x00;
    McastMac->Addr[2] = 0x5E;

    // Lower 23 bits from ipv4 address
    McastMac->Addr[3] = (Ip->v4.Addr[1] & 0x7F); // Clear the most significant bit (25th bit of MAC must be 0)
    McastMac->Addr[4] = Ip->v4.Addr[2];
    McastMac->Addr[5] = Ip->v4.Addr[3];
  } else {
    // Most significant 16 bits of multicast v6 HW address are set
    // 33-33 is the IPv6 Ethernet Multicast Address (see RFC 2464)
    McastMac->Addr[0] = 0x33;
    McastMac->Addr[1] = 0x33;

    // lower four octets are taken from ipv6 address
    McastMac->Addr[2] = Ip->v6.Addr[8];
    McastMac->Addr[3] = Ip->v6.Addr[9];
    McastMac->Addr[4] = Ip->v6.Addr[10];
    McastMac->Addr[5] = Ip->v6.Addr[11];
  }

  return EFI_SUCCESS;
}

/*
 *  UEFI NvData() function
 *
 */
EFI_STATUS
EFIAPI
SnpNvData (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* pobj,
  IN        BOOLEAN read_write,
  IN        UINTN offset,
  IN        UINTN buff_size,
  IN  OUT   VOID *data
  )
{
  DEBUG ((DEBUG_NET, "SnpNvData()\n"));

  return EFI_UNSUPPORTED;
}


/*
 *  UEFI GetStatus () function
 *
 */
EFI_STATUS
EFIAPI
SnpGetStatus (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
      OUT   UINT32 *IrqStat  OPTIONAL,
      OUT   VOID **TxBuff    OPTIONAL
  )
{
  UINT32          FifoInt;
  EFI_STATUS      Status;
  UINTN           NumTxStatusEntries;
  UINT32          TxStatus;
  UINT16          PacketTag;
  UINT32          Interrupts;
  LAN9118_DRIVER *LanDriver;

  LanDriver = INSTANCE_FROM_SNP_THIS (Snp);

  // Check preliminaries
  if (Snp == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (Snp->Mode->State != EfiSimpleNetworkInitialized) {
    return EFI_NOT_STARTED;
  }

  // Check and acknowledge TX Status interrupt (this will happen if the
  // consumer of SNP does not call GetStatus.)
  // TODO will we lose TxStatuses if this happens? Maybe in SnpTransmit we
  // should check for it and dump the TX Status FIFO.
  FifoInt = MmioRead32 (LAN9118_FIFO_INT);

  // Clear the TX Status FIFO Overflow
  if ((FifoInt & INSTS_TXSO) == 0) {
    FifoInt |= INSTS_TXSO;
    MmioWrite32 (LAN9118_FIFO_INT, FifoInt);
  }

  // Read interrupt status if IrqStat is not NULL
  if (IrqStat != NULL) {

    // Check for receive interrupt
    if (MmioRead32 (LAN9118_INT_STS) & INSTS_RSFL) { // Data moved from rx FIFO
      *IrqStat |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
      MmioWrite32 (LAN9118_INT_STS,INSTS_RSFL);
    } else {
      *IrqStat &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
    }

    // Check for transmit interrupt
    if (MmioRead32 (LAN9118_INT_STS) & INSTS_TSFL) {
      *IrqStat |= EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
      MmioWrite32 (LAN9118_INT_STS,INSTS_TSFL);
    } else {
      *IrqStat &= ~EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
    }

    // Check for software interrupt
    if (MmioRead32 (LAN9118_INT_STS) & INSTS_SW_INT) {
      *IrqStat |= EFI_SIMPLE_NETWORK_SOFTWARE_INTERRUPT;
      MmioWrite32 (LAN9118_INT_STS,INSTS_SW_INT);
    } else {
      *IrqStat &= ~EFI_SIMPLE_NETWORK_SOFTWARE_INTERRUPT;
    }
  }

  // Check Status of transmitted packets
  // (We ignore TXSTATUS_NO_CA has it might happen in Full Duplex)

  NumTxStatusEntries = MmioRead32(LAN9118_TX_FIFO_INF) & TXFIFOINF_TXSUSED_MASK;
  if (NumTxStatusEntries > 0) {
    TxStatus = MmioRead32 (LAN9118_TX_STATUS);
    PacketTag = TxStatus >> 16;
    TxStatus = TxStatus & 0xFFFF;
    if ((TxStatus & TXSTATUS_ES) && TxStatus != (TXSTATUS_ES | TXSTATUS_NO_CA)) {
      DEBUG ((EFI_D_ERROR, "LAN9118: There was an error transmitting. TxStatus=0x%08x:", TxStatus));
      if (TxStatus & TXSTATUS_NO_CA) {
        DEBUG ((EFI_D_ERROR, "- No carrier\n"));
      }
      if (TxStatus & TXSTATUS_DEF) {
        DEBUG ((EFI_D_ERROR, "- Packet tx was deferred\n"));
      }
      if (TxStatus & TXSTATUS_EDEF) {
        DEBUG ((EFI_D_ERROR, "- Tx ended because of excessive deferral\n"));
      }
      if (TxStatus & TXSTATUS_ECOLL) {
        DEBUG ((EFI_D_ERROR, "- Tx ended because of Excessive Collisions\n"));
      }
      if (TxStatus & TXSTATUS_LCOLL) {
        DEBUG ((EFI_D_ERROR, "- Packet Tx aborted after coll window of 64 bytes\n"));
      }
      if (TxStatus & TXSTATUS_LOST_CA) {
        DEBUG ((EFI_D_ERROR, "- Lost carrier during Tx\n"));
      }
      return EFI_DEVICE_ERROR;
    } else {
      LanDriver->Stats.TxTotalFrames += 1;
      *TxBuff = LanDriver->TxRing[PacketTag % LAN9118_TX_RING_NUM_ENTRIES];
    }
  }

  // Check for a TX Error interrupt
  Interrupts = MmioRead32 (LAN9118_INT_STS);
  if (Interrupts & INSTS_TXE) {
    DEBUG ((EFI_D_ERROR, "LAN9118: Transmitter error. Restarting..."));

    // Initiate a software reset
    if (SoftReset (0, Snp) < 0) {
      DEBUG ((EFI_D_ERROR, "\n\tSoft Reset Failed: Hardware Error\n"));
      return EFI_DEVICE_ERROR;
    }

    // Acknowledge the TXE
    MmioWrite32 (LAN9118_INT_STS, INSTS_TXE);
    gBS->Stall (LAN9118_STALL);

    // Restart the transmitter
    StartTx (START_TX_MAC | START_TX_CFG, Snp);
  }

  // Update the media status
  Status = CheckLinkStatus (0, Snp);
  if (EFI_ERROR(Status)) {
    Snp->Mode->MediaPresent = FALSE;
  } else {
    Snp->Mode->MediaPresent = TRUE;
  }

  return EFI_SUCCESS;
}


/*
 *  UEFI Transmit() function
 *
 */
EFI_STATUS
EFIAPI
SnpTransmit (
  IN  EFI_SIMPLE_NETWORK_PROTOCOL  *Snp,
  IN  UINTN                        HdrSize,
  IN  UINTN                        BuffSize,
  IN  VOID*                        Data,
  IN  EFI_MAC_ADDRESS              *SrcAddr  OPTIONAL,
  IN  EFI_MAC_ADDRESS              *DstAddr  OPTIONAL,
  IN  UINT16                       *Protocol OPTIONAL
  )
{
  LAN9118_DRIVER *LanDriver;
  UINT32 TxFreeSpace;
  UINT32 TxStatusSpace;
  INT32 Count;
  UINT32 CommandA;
  UINT32 CommandB;
  UINT16 LocalProtocol;
  UINT32 *LocalData;
  UINT16 PacketTag;

#if defined(EVAL_PERFORMANCE)
  UINT64 Perf;
  UINT64 StartClock;
  UINT64 EndClock;

  Perf = GetPerformanceCounterProperties (NULL, NULL);
  StartClock = GetPerformanceCounter ();
#endif

  LanDriver = INSTANCE_FROM_SNP_THIS (Snp);

  // Check preliminaries
  if ((Snp == NULL) || (Data == NULL)) {
    return EFI_INVALID_PARAMETER;
  }
  if (Snp->Mode->State != EfiSimpleNetworkInitialized) {
    return EFI_NOT_STARTED;
  }

  // Ensure header is correct size if non-zero
  if (HdrSize) {
    if (HdrSize != Snp->Mode->MediaHeaderSize) {
      return EFI_INVALID_PARAMETER;
    }

    if ((DstAddr == NULL) || (Protocol == NULL)) {
      return EFI_INVALID_PARAMETER;
    }
  }

  // Before transmitting check the link status
  /*if (CheckLinkStatus (0, Snp) < 0) {
    return EFI_NOT_READY;
  }*/

  // Get DATA FIFO free space in bytes
  TxFreeSpace = TxDataFreeSpace (0, Snp);
  if (TxFreeSpace < BuffSize) {
    return EFI_NOT_READY;
  }

  // Get STATUS FIFO used space in bytes
  TxStatusSpace = TxStatusUsedSpace (0, Snp);
  if (TxStatusSpace > 500) {
    return EFI_NOT_READY;
  }

  // If DstAddr is not provided, get it from Buffer (we trust that the caller
  // has provided a well-formed frame).
  if (DstAddr == NULL) {
    DstAddr = (EFI_MAC_ADDRESS *) Data;
  }

  // Check for the nature of the frame
  if ((DstAddr->Addr[0] & 0x1) == 1) {
    LanDriver->Stats.TxMulticastFrames += 1;
  } else {
    LanDriver->Stats.TxUnicastFrames += 1;
  }

  // Check if broadcast
  if (DstAddr->Addr[0] == 0xFF) {
    LanDriver->Stats.TxBroadcastFrames += 1;
  }

  PacketTag = LanDriver->NextPacketTag;
  LanDriver->NextPacketTag++;

  if (HdrSize) {

    // Format pointer
    LocalData = (UINT32*) Data;
    LocalProtocol = *Protocol;

    // Create first buffer to pass to controller (for the header)
    CommandA = TX_CMD_A_FIRST_SEGMENT | TX_CMD_A_BUFF_SIZE (HdrSize);
    CommandB = TX_CMD_B_PACKET_TAG (PacketTag) | TX_CMD_B_PACKET_LENGTH (BuffSize);

    // Write the commands first
    MmioWrite32 (LAN9118_TX_DATA, CommandA);
    MmioWrite32 (LAN9118_TX_DATA, CommandB);

    // Write the destination address
    MmioWrite32 (LAN9118_TX_DATA,
               (DstAddr->Addr[0]) |
               (DstAddr->Addr[1] << 8) |
               (DstAddr->Addr[2] << 16) |
               (DstAddr->Addr[3] << 24)
               );

    MmioWrite32 (LAN9118_TX_DATA,
               (DstAddr->Addr[4]) |
               (DstAddr->Addr[5] << 8) |
               (SrcAddr->Addr[0] << 16) | // Write the Source Address
               (SrcAddr->Addr[1] << 24)
               );

    MmioWrite32 (LAN9118_TX_DATA,
               (SrcAddr->Addr[2]) |
               (SrcAddr->Addr[3] << 8) |
               (SrcAddr->Addr[4] << 16) |
               (SrcAddr->Addr[5] << 24)
               );

    // Write the Protocol
    MmioWrite32 (LAN9118_TX_DATA, (UINT32)(HTONS (LocalProtocol)));

    // Next buffer is the payload
    CommandA = TX_CMD_A_LAST_SEGMENT | TX_CMD_A_BUFF_SIZE (BuffSize - HdrSize) | TX_CMD_A_COMPLETION_INT | TX_CMD_A_DATA_START_OFFSET (2); // 2 bytes beginning offset

    // Write the commands
    MmioWrite32 (LAN9118_TX_DATA, CommandA);
    MmioWrite32 (LAN9118_TX_DATA, CommandB);

    // Write the payload
    for (Count = 0; Count < ((BuffSize + 3) >> 2) - 3; Count++) {
      MmioWrite32 (LAN9118_TX_DATA, LocalData[Count + 3]);
    }
  } else {
    // Format pointer
    LocalData = (UINT32*) Data;

    // Create a buffer to pass to controller
    CommandA = TX_CMD_A_FIRST_SEGMENT | TX_CMD_A_LAST_SEGMENT | TX_CMD_A_BUFF_SIZE (BuffSize) | TX_CMD_A_COMPLETION_INT;
    CommandB = TX_CMD_B_PACKET_TAG (PacketTag) | TX_CMD_B_PACKET_LENGTH (BuffSize);

    // Write the commands first
    MmioWrite32 (LAN9118_TX_DATA, CommandA);
    MmioWrite32 (LAN9118_TX_DATA, CommandB);

    // Write all the data
    for (Count = 0; Count < ((BuffSize + 3) >> 2); Count++) {
      MmioWrite32 (LAN9118_TX_DATA, LocalData[Count]);
    }
  }

  // Save the address of the submitted packet so we can notify the consumer that
  // it has been sent in GetStatus. When the packet tag appears in the Tx Status
  // Fifo, we will return Buffer in the TxBuff parameter of GetStatus.
  LanDriver->TxRing[PacketTag % LAN9118_TX_RING_NUM_ENTRIES] = Data;

#if defined(EVAL_PERFORMANCE)
  EndClock = GetPerformanceCounter ();
  DEBUG ((EFI_D_ERROR, "Time processing: %d counts @ %d Hz\n", StartClock - EndClock,Perf));
#endif

  LanDriver->Stats.TxGoodFrames += 1;

  return EFI_SUCCESS;
}


/*
 *  UEFI Receive() function
 *
 */
EFI_STATUS
EFIAPI
SnpReceive (
  IN        EFI_SIMPLE_NETWORK_PROTOCOL* Snp,
      OUT   UINTN *HdrSize                OPTIONAL,
  IN  OUT   UINTN *BuffSize,
      OUT   VOID *Data,
      OUT   EFI_MAC_ADDRESS *SrcAddr      OPTIONAL,
      OUT   EFI_MAC_ADDRESS *DstAddr      OPTIONAL,
      OUT   UINT16 *Protocol              OPTIONAL
  )
{
  LAN9118_DRIVER *LanDriver;
  UINT32 RxFifoStatus;
  UINT32 NumPackets;
  UINT32 RxCfgValue;
  UINT32 PLength; // Packet length
  UINT32 ReadLimit;
  UINT32 Count;
  UINT32 Padding;
  UINT32 *RawData;
  EFI_MAC_ADDRESS Dst;
  EFI_MAC_ADDRESS Src;
  UINTN  DroppedFrames;

  LanDriver = INSTANCE_FROM_SNP_THIS (Snp);

#if defined(EVAL_PERFORMANCE)
  UINT64 Perf = GetPerformanceCounterProperties (NULL, NULL);
  UINT64 StartClock = GetPerformanceCounter ();
#endif

  // Check preliminaries
  if ((Snp == NULL) || (Data == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  if (Snp->Mode->State != EfiSimpleNetworkInitialized) {
    return EFI_NOT_STARTED;
  }

  // Count dropped frames
  DroppedFrames = MmioRead32 (LAN9118_RX_DROP);
  LanDriver->Stats.RxDroppedFrames += DroppedFrames;

  NumPackets = RxStatusUsedSpace (0, Snp) / 4;
  if (!NumPackets) {
    return EFI_NOT_READY;
  }

  // Read Rx Status (only if not empty)
  RxFifoStatus = MmioRead32 (LAN9118_RX_STATUS);
  LanDriver->Stats.RxTotalFrames += 1;

  // First check for errors
  if ((RxFifoStatus & RXSTATUS_MII_ERROR) ||
      (RxFifoStatus & RXSTATUS_RXW_TO) ||
      (RxFifoStatus & RXSTATUS_FTL) ||
      (RxFifoStatus & RXSTATUS_LCOLL) ||
      (RxFifoStatus & RXSTATUS_LE) ||
      (RxFifoStatus & RXSTATUS_DB))
  {
    DEBUG ((EFI_D_WARN, "Warning: There was an error on frame reception.\n"));
    return EFI_DEVICE_ERROR;
  }

  // Check if we got a CRC error
  if (RxFifoStatus & RXSTATUS_CRC_ERROR) {
    DEBUG ((EFI_D_WARN, "Warning: Crc Error\n"));
    LanDriver->Stats.RxCrcErrorFrames += 1;
    LanDriver->Stats.RxDroppedFrames += 1;
    return EFI_DEVICE_ERROR;
  }

  // Check if we got a runt frame
  if (RxFifoStatus & RXSTATUS_RUNT) {
    DEBUG ((EFI_D_WARN, "Warning: Runt Frame\n"));
    LanDriver->Stats.RxUndersizeFrames += 1;
    LanDriver->Stats.RxDroppedFrames += 1;
    return EFI_DEVICE_ERROR;
  }

  // Check filtering status for this packet
  if (RxFifoStatus & RXSTATUS_FILT_FAIL) {
    DEBUG ((EFI_D_WARN, "Warning: Frame Failed Filtering\n"));
    // fast forward?
  }

  // Check if we got a broadcast frame
  if (RxFifoStatus & RXSTATUS_BCF) {
    LanDriver->Stats.RxBroadcastFrames += 1;
  }

  // Check if we got a multicast frame
  if (RxFifoStatus & RXSTATUS_MCF) {
    LanDriver->Stats.RxMulticastFrames += 1;
  }

  // Check if we got a unicast frame
  if ((RxFifoStatus & RXSTATUS_BCF) && ((RxFifoStatus & RXSTATUS_MCF) == 0)) {
    LanDriver->Stats.RxUnicastFrames += 1;
  }

  // Get the received packet length
  PLength = GET_RXSTATUS_PACKET_LENGTH(RxFifoStatus);
  LanDriver->Stats.RxTotalBytes += (PLength - 4);

  // Check buffer size
  if (*BuffSize < PLength) {
    *BuffSize = PLength;
    return EFI_BUFFER_TOO_SMALL;
  }

  // If padding is applied, read more DWORDs
  if (PLength % 4) {
    Padding = 4 - (PLength % 4);
    ReadLimit = (PLength + Padding)/4;
  } else {
    ReadLimit = PLength/4;
    Padding = 0;
  }

  // Set the amount of data to be transfered out of FIFO for THIS packet
  // This can be used to trigger an interrupt, and status can be checked
  RxCfgValue = MmioRead32 (LAN9118_RX_CFG);
  RxCfgValue &= ~(RXCFG_RX_DMA_CNT_MASK);
  RxCfgValue |= RXCFG_RX_DMA_CNT (ReadLimit);

  // Set end alignment to 4-bytes
  RxCfgValue &= ~(RXCFG_RX_END_ALIGN_MASK);
  MmioWrite32 (LAN9118_RX_CFG, RxCfgValue);

  // Update buffer size
  *BuffSize = PLength; // -4 bytes may be needed: Received in buffer as
                       // 4 bytes longer than packet actually is, unless
                       // packet is < 64 bytes

  if (HdrSize != NULL)
    *HdrSize = Snp->Mode->MediaHeaderSize;

  // Format the pointer
  RawData = (UINT32*)Data;

  // Read Rx Packet
  for (Count = 0; Count < ReadLimit; Count++) {
    RawData[Count] = MmioRead32 (LAN9118_RX_DATA);
  }

  // Check for Rx errors (worst possible error)
  if (MmioRead32 (LAN9118_INT_STS) & INSTS_RXE) {
    DEBUG ((EFI_D_WARN, "Warning: Receiver Error. Restarting...\n"));

    // Initiate a software reset
    if (SoftReset (0, Snp) < 0) {
      DEBUG ((EFI_D_ERROR, "Error: Soft Reset Failed: Hardware Error.\n"));
      return EFI_DEVICE_ERROR;
    }

    // Acknowledge the RXE
    MmioWrite32 (LAN9118_INT_STS, INSTS_RXE);
    gBS->Stall (LAN9118_STALL);

    // Restart the rx (and do not clear FIFO)
    StartRx (0, Snp);

    // Say that command could not be sent
    return EFI_DEVICE_ERROR;
  }

  // Get the destination address
  if (DstAddr != NULL) {
    Dst.Addr[0] = (RawData[0] & 0xFF);
    Dst.Addr[1] = (RawData[0] & 0xFF00) >> 8;
    Dst.Addr[2] = (RawData[0] & 0xFF0000) >> 16;
    Dst.Addr[3] = (RawData[0] & 0xFF000000) >> 24;
    Dst.Addr[4] = (RawData[1] & 0xFF);
    Dst.Addr[5] = (RawData[1] & 0xFF00) >> 8;
    CopyMem (DstAddr, &Dst, NET_ETHER_ADDR_LEN);
  }

  // Get the source address
  if (SrcAddr != NULL) {
    Src.Addr[0] = (RawData[1] & 0xFF0000) >> 16;
    Src.Addr[1] = (RawData[1] & 0xFF000000) >> 24;
    Src.Addr[2] = (RawData[2] & 0xFF);
    Src.Addr[3] = (RawData[2] & 0xFF00) >> 8;
    Src.Addr[4] = (RawData[2] & 0xFF0000) >> 16;
    Src.Addr[5] = (RawData[2] & 0xFF000000) >> 24;
    CopyMem (SrcAddr,&Src, NET_ETHER_ADDR_LEN);
  }

  // Get the protocol
  if (Protocol != NULL) {
    *Protocol = NTOHS (RawData[3] & 0xFFFF);
  }

#if defined(EVAL_PERFORMANCE)
  UINT64 EndClock = GetPerformanceCounter ();
  DEBUG ((EFI_D_ERROR, "Receive Time processing: %d counts @ %d Hz\n", StartClock - EndClock,Perf));
#endif

  LanDriver->Stats.RxGoodFrames += 1;

  return EFI_SUCCESS;
}